ABC | Volume 110, Nº1, January 2018

Original Article Pitanga et al Physical activity and cardiovascular risk factors Arq Bras Cardiol. 2018; 110(1):36-43 for both gender. 32 Data from ELSA-Brasil which are unpublished yet suggest that active commuting, more common in less privileged social strata, is more likely to reflect inequalities in urban mobility across Brazilian cities than a healthy habit. The mechanisms by which PA reduces BP, blood glucose, and lipid profile remain speculative. Recent studies have emphasized the need for further research to better understand the cellular and molecular aspects involved in the main health benefits induced by PA. 33 Relevant evidence for PA, according to the American College of Sports Medicine (ACSM), 15 is: a) decrease in insulin levels with consequent reduction of renal sodium retention and basal sympathetic tone; b) reduction of catecholamine release levels; c) release of vasodilator substances in circulation by skeletal muscles. As to lipid profile, there is little information about the mechanisms responsible for the reduction of LDL-C levels and very low-density lipoprotein (VLDL-C) dosage. However, the main reason for evaluating HDL-C is the greater action of lipoprotein lipase (LPL) in response to exercise: LPL accelerates VLDL-C decomposition, thus moving triglycerides from bloodstream to muscles; This causes cholesterol and other substances to be transferred to HDL-C, thereby increasing its concentration. 16 PA also seems to play an important role in reducing blood glucose levels because it promotes proliferation of capillaries, increasing LPL activity in the muscles — which in turn increases insulin sensitivity. In addition, higher levels of PA may increase oxidative muscle fibers, which are more sensitive to insulin and can reduce glycemia. 17 A highlight of the study is that the sample was a cohort of volunteers consisting of public servants; although they do not represent the general population, there was a significant number of participants from six Brazilian capitals. Calculation of different cardiovascular risk scores is another strong point, for it allowed us to analyze the association between them and both LTPA and CPA. A possible limitation of the study (memory bias) can be attributed to information about PA obtained through questionnaires, even though this is an instrument widely used in national and international studies. It is important to mention that ELSA-Brasil was a longitudinal study, therefore it is expected to incorporate a more objective measure — the accelerometry — which may increase the validity of information about PA. Conclusions LTPA was shown to be associated with the cardiovascular risk scores analyzed, but CPA was not. The amount of physical activity (duration and intensity) was more significantly associated with cardiovascular risk scores in ELSA Brazil. Our results can bring important contributions to public health, since the management of public policies that promote PA can be influenced by the knowledge about type of PA that bring more health benefits. Knowing that LTPA is associated with cardiovascular risk decrease while CPA is not should be taken to public health authorities so that actions encouraging exercises in leisure and free time can be implemented. Important to note that, although association between CPA and cardiovascular risk was not established, active commuting— such as walking and cycling — should be encouraged in certain population groups, especially when displacement to work is made at moderate intensities. Furthermore, considering dose- response effects found, especially inmen, the population should be encouraged to practice more PA tomaximize health benefits. Author contributions Conception and design of the research: Alvim S, Almeida MC, Aquino EML; Acquisition of data and Obtaining financing: Alvim S, Almeida MC, Barreto SM, Aquino EML; Analysis and interpretation of the data: Pitanga FJG, Alvim S, Almeida MC, Aquino EML; Statistical analysis: Pitanga FJG, Almeida MC; Writing of the manuscript: Pitanga FJG; Critical revision of the manuscript for intellectual content: Pitanga FJG, Alvim S, Almeida MC, Barreto SM, Aquino EML. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding This study was funded by Ministério da Saúde do Brasil, Ministério de Ciência e Tecnologia do Brasil and CNPq, process nº 01 06 0010.00RS, 01 06 0212.00BA, 01 06 0300.00ES, 01 06 0278.00MG, 01 06 0115.00SP, 01 06 0071.00RJ. Study Association This study is not associatedwith any thesis or dissertationwork. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Instituto de Saúde Coletiva da UFBA under the protocol number 027.06/CEP-ISC. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 41